To maximize the number of vehicles passing by the stop-line in a cycle and improve the operation efficiency of intersection in China, the settlement of left-turn lane waiting-zone is becoming prevailing. Based on conf...To maximize the number of vehicles passing by the stop-line in a cycle and improve the operation efficiency of intersection in China, the settlement of left-turn lane waiting-zone is becoming prevailing. Based on conflicting-point method, the internal mechanism of left-turn flow after stopping line was analyzed through taking postposition left-turn lane waiting-zone intersection for instance. The relationship between the first left-turn vehicle and the last vehicle of previous phase passing the conflicting point was expounded. According to the time of successive arriving of two vehicle flows at conflicting-point, the reasonable layout for waiting area of left-turn vehicles was researched when the clearance index was less than O. The results suggest that the appropriate layout for waiting area of left-turning vehicles can improve the operation efficiency of intersections.展开更多
Background The timely and appropriate monitoring of pulmonary status is of utmost importance for patients with cystic fibrosis(CF).Computed tomography(CT)has been used in clinical and research settings for tracking lu...Background The timely and appropriate monitoring of pulmonary status is of utmost importance for patients with cystic fibrosis(CF).Computed tomography(CT)has been used in clinical and research settings for tracking lung involvement in CF patients.However,as CT delivers a considerable amount of radiation,its sequential use in CF patients remains a concern.The application of CT,therefore,should take into account its potential risks.This review aims to understand whether and to what extent the CT findings correlate with the findings from other monitoring tools in CF lung disease.Data sources PubMed was searched for articles about the correlation of chest CT findings with spirometric indices and with lung clearance index in children and adolescents with CF.The most relevant articles were reviewed and are presented herein.Results Most studies have shown that forced expiratory volume in the first second(FEV,)and other spirometric indices correlate moderately with CT structural lung damage.However,at the individual level,there were patients with FEV,within the normal range and abnormal CT and vice versa.Furthermore,longitudinal studies have indicated that the deterioration of structural lung damage does not occur in parallel with the progression of lung function.Lung clearance index is a better predictor of CT findings.Conclusions In general,the existing studies do not support the use of lung function tests as surrogates of chest CT.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.70631002)Youth Science &Technology Foundation of Xi’an University of Architecture &Technology(Grant No.0608)
文摘To maximize the number of vehicles passing by the stop-line in a cycle and improve the operation efficiency of intersection in China, the settlement of left-turn lane waiting-zone is becoming prevailing. Based on conflicting-point method, the internal mechanism of left-turn flow after stopping line was analyzed through taking postposition left-turn lane waiting-zone intersection for instance. The relationship between the first left-turn vehicle and the last vehicle of previous phase passing the conflicting point was expounded. According to the time of successive arriving of two vehicle flows at conflicting-point, the reasonable layout for waiting area of left-turn vehicles was researched when the clearance index was less than O. The results suggest that the appropriate layout for waiting area of left-turning vehicles can improve the operation efficiency of intersections.
文摘Background The timely and appropriate monitoring of pulmonary status is of utmost importance for patients with cystic fibrosis(CF).Computed tomography(CT)has been used in clinical and research settings for tracking lung involvement in CF patients.However,as CT delivers a considerable amount of radiation,its sequential use in CF patients remains a concern.The application of CT,therefore,should take into account its potential risks.This review aims to understand whether and to what extent the CT findings correlate with the findings from other monitoring tools in CF lung disease.Data sources PubMed was searched for articles about the correlation of chest CT findings with spirometric indices and with lung clearance index in children and adolescents with CF.The most relevant articles were reviewed and are presented herein.Results Most studies have shown that forced expiratory volume in the first second(FEV,)and other spirometric indices correlate moderately with CT structural lung damage.However,at the individual level,there were patients with FEV,within the normal range and abnormal CT and vice versa.Furthermore,longitudinal studies have indicated that the deterioration of structural lung damage does not occur in parallel with the progression of lung function.Lung clearance index is a better predictor of CT findings.Conclusions In general,the existing studies do not support the use of lung function tests as surrogates of chest CT.
